The DH is a major factor in this. Leagues without the DH will use the extreme platoon relievers in disadvantageous situations much more often -- self-explanatory with pinch-hitting and all. DH leagues at lower caps (80 and 100) allow pitchers to cruise if they are 9*, so less chance of bad situations for the extreme cheap relievers.
In DH leagues if you have a Four Ace 9* strategy, the cheap, extreme relievers under 1M are fine. Usually for a luxury, I like a guy like Otis Lambeth $1.34M as the E type that Hal would go to amongst a bunch of extreme split relievers. Like this team in a $80M DH league:
https://365.strat-o-matic.com/team/1802385Salary cap is also another factor, totally changes when you're in a $140M or $200M league, of course better relievers.
Ballpark, too, is a factor. Have no data, but it seems that small ball teams at lower caps would -- or need to -- win more of those 1 run games, whereas the bomber teams, and especially those at high caps, are involved in games with many more runs. Runs are more scarce in small ball venues, obviously.
Division opponents matter as well -- are they lefty, righty, bomber parks, small ball? So, a lot of variables and factors across different salary caps and roster construction, pitching in particular.
That said, I probably agree on points above -- in lower caps, think that a couple extreme cheap relievers under $1M and an E reliever or two slightly over $1M seems like an optimal strategy with a Four Ace strategy *9. You can stretch it with an *8 in that rotation as well to free up a little money. I even sometimes like a *7 guy like Scherzer -- the 8R -- paired with *9 aces if a lot of righty parks are in the division or league.